1. Field of the Invention
The present invention relates to the tuning of musical instruments, and more particularly to a multi-tuner bridge for a stringed musical instrument in which each of the strings can be instantly retuned to one of three preset positions.
2. Description of the Related Art
Stringed musical instruments, such as guitars, are widely enjoyed by both musicians and music lovers alike, due to the wide range of sounds which they can produce. This musical range stems from the fact that the instruments have a plurality of strings, each of which can be tuned to produce a distinct musical note. The note produced by the strings is dependent upon the thickness of the string, the intonation, or effective length of the string, and the tension of the string. Most stringed instruments are equipped with tuning pegs at an end of the strings, which can be adjusted to vary the tension on the strings, and a bridge fixed in place at the opposite end of the strings from the tuning pegs. The bridge defines an effective end to the length of the strings. As the tuning pegs are tightened, the frequency produced by the vibrating string is increased, raising the pitch of the note. Once the instrument has been tuned by adjusting the tuning pegs to the proper settings, the instrument cannot be retuned to new settings without readjusting the tuning pegs.
It is very common for musicians performing on stage to require their instruments to be tuned to different settings, or keys, to accommodate the playing of different songs. Since the musician cannot just stop the performance and retune the instrument, it is common for the musician to have numerous instruments, each of which are tuned to a different key or setting. This presents obvious problems to the musician, in that several instruments may be required, and that it is quite cumbersome to change instruments mid-performance.
Devices for musical instruments which alter the tension of the guitar strings are known in the prior art. One such prior art string tension varying device is commonly known as a "tremolo" bridge. The tremolo bridge comprises a handle which extends from the bridge plate on the body of the guitar. By pulling back on the handle, the musician increases the tension on each of the strings, which has the effect of increasing the pitch of the strings. Conversely, by pushing down on the handle, the string tension decreases which decreases the pitch. However, a drawback with the tremolo bridge is that the strings are not retuned to a fixed position. Instead, the strings are temporarily stretched or loosened, and they return to their tuned position once the musician lets go of the handle.
An improved solution to this problem was provided in the prior art by U.S. Pat. No. 4,535,670, issued Aug. 20, 1985, by Borisoff, the inventor in this case. The prior art device discloses an attachment for a stringed musical instrument having an actuator arm which can be manipulated by the musician to precisely change the pitch of the strings. The actuator arm is pivotally connected to a rocker arm, which in turn engages an end of the string. The rocker arm can pivot relative the instrument body to increase or decrease the tension of the string. By manipulating the actuator arm, an operator can change the tension on the string from a first tension to a second tension. The musician can set the string to a first pitch by adjusting the associated tuning peg, and to a second pitch by adjusting a tuning screw associated with an end of the rocker arm. However, this prior art device is quite limited, in that it only enables the selection between two preset tuning positions, and does not allow for the adjustment of intonation.
In addition, the prior art device cannot be readily adapted for use in an acoustic instrument, such as an acoustic guitar. An acoustic guitar has a generally hollow body. The front or facing surface of the body is known as the soundboard, and the strings generally terminate at a bridge affixed to a portion of the soundboard. The amplification of the vibrating strings is provided by the resonance of the soundboard in association with the cavity defined by the hollow body. Accordingly, external devices, such as the prior art device, cannot be affixed to the soundboard without significantly altering its acoustic characteristics. Additionally, the lightweight materials often used in acoustic instruments could potentially be damaged by the stress induced by the altering tension of the strings.
An additional problem with adapting the prior art device to an acoustic guitar is that of "cabinet drop." As the tension on individual strings is increased or decreased, the acoustic guitar body can bow or warp due to the increased string tension. The resulting change in shape of the guitar body directly affects the tension of the strings adjacent to the ones being retuned. Thus, as one string is tightened the adjacent strings become loosened, and as the string is loosened the adjacent strings become tightened. This change to the adjacent string tension is known as "cabinet drop."
Thus, it would be desirable to provide a bridge for a stringed instrument capable of providing the musician with three preset tuning positions per string. It would be further desirable to provide a bridge for a stringed musical instrument capable of permitting variations in intonation. It would be further desirable to provide a bridge for an acoustic musical instrument having a hollow body, capable of providing a musician with instant access to three preset tuning positions per string. It would be still further desirable to provide a mechanism for structurally reinforcing an acoustic guitar without altering the acoustic characteristics of the soundboard to prevent structural damage to the instrument or cabinet drop.